package org.apache.bcel.verifier.structurals;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
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 *
 * 5. Products derived from this software may not be called "Apache",
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import org.apache.bcel.generic.*;


import java.util.HashSet;
import java.util.Hashtable;

/**
 * This class allows easy access to ExceptionHandler objects.
 *
 * @version $Id: ExceptionHandlers.java,v 1.2 2006/09/04 15:43:18 andos Exp $
 * @author <A HREF="http://www.inf.fu-berlin.de/~ehaase"/>Enver Haase</A>
 */
public class ExceptionHandlers{
	/**
	 * The ExceptionHandler instances.
	 * Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances.
	 */
	private Hashtable<InstructionHandle, HashSet> exceptionhandlers;
	 
	/**
	 * Constructor. Creates a new ExceptionHandlers instance.
	 */
	public ExceptionHandlers(MethodGen mg){
		exceptionhandlers = new Hashtable<InstructionHandle, HashSet> ();
		CodeExceptionGen[] cegs = mg.getExceptionHandlers();
		for (int i=0; i<cegs.length; i++){
			ExceptionHandler eh = new ExceptionHandler(cegs[i].getCatchType(), cegs[i].getHandlerPC());
			for (InstructionHandle ih=cegs[i].getStartPC(); ih != cegs[i].getEndPC().getNext(); ih=ih.getNext()){
				HashSet<ExceptionHandler> hs;
				hs = (HashSet) exceptionhandlers.get(ih);
				if (hs == null){
					hs = new HashSet<ExceptionHandler>();
					exceptionhandlers.put(ih, hs);
				}
				hs.add(eh);
			}
		}
	}
	
	/**
	 * Returns all the ExceptionHandler instances representing exception
	 * handlers that protect the instruction ih.
	 */
	public ExceptionHandler[] getExceptionHandlers(InstructionHandle ih){
		HashSet hs = (HashSet) exceptionhandlers.get(ih);
		if (hs == null) return new ExceptionHandler[0];
		else{
			ExceptionHandler[] ret = new ExceptionHandler[hs.size()];
			return (ExceptionHandler[]) (hs.toArray(ret));
		}
	}

}
